WO2004088922A1

WO2004088922A1 - Network designing system

Info

Publication number: WO2004088922A1
Application number: PCT/JP2003/004099
Authority: WO
Inventors: Norihiko Shinomiya; Akira Chugo; Keiji Miyazaki; Masatake Miyabe
Original assignee: Fujitsu Limited
Priority date: 2003-03-31
Filing date: 2003-03-31
Publication date: 2004-10-14
Also published as: EP1610493A1; WO2004088921A1; EP2528257A2; JPWO2004088921A1; EP2528257A3; CN1717897A; EP1610493A4; JP4053044B2; CN100373860C; EP1610493B1

Abstract

A system for designing a network having a plurality of channels and including branch nodes, comprising means for dividing the network into a plurality of linear partial networks terminating at a terminal node or a branch node by assigning a channel terminating apparatus to the terminal node and each branch node, means for assigning a linear repeater or a reproduction repeater to each node constituting each partial network based on the signal performance, means for forming a specific path by combining respective partial networks assigned with the linear repeater or the reproduction repeater by the assigning means, and means for deleting a channel terminating apparatus assigned to a branch node for each path formed by the path forming means based the signal performance.

Description

Description Network design equipment Technical field

The present invention relates to a method and apparatus for designing a photonic network that enables high-speed and inexpensive communication of a large amount of information. Background art

There is a need for technology that enables a variety of multimedia services to be used at any time and place. One such technology is photonic network technology, which enables high-speed and inexpensive communication of large amounts of information. Among photonic network technologies, a WDM (Wavelength Division Multiplexing) technology that multiplexes and communicates multiple optical signals with different wavelengths using a single optical fiber, and configures a network by considering each wavelength as one communication path Photonic node technology is evolving. With this development, it is necessary to realize a communication network system (hereinafter referred to as a communication network) that minimizes the equipment installation cost (equipment cost) while maintaining high reliability in signal reachability.

The communication network consists of a linear repeater (1R), a regenerative repeater (3R), and a branching unit (HUB). Each device is located in a designated station. The linear repeater amplifies the signal received by itself with a predetermined gain to compensate for the signal attenuation. In a linear repeater, noise mixed into the main signal may be amplified together with the main signal by signal amplification. For this reason, in a linear repeater, the signal-to-noise ratio (S / N ratio) may be degraded, making it impossible to reproduce on the receiving side.

The regenerative repeater includes a regenerator. The regenerative repeater first divides the multiplexed signal received by itself into respective channels. Next, in the regenerative repeater, the regenerator performs light-to-electric conversion for each channel, performs signal regeneration, reproduced signal amplification, and electricity-to-light conversion. In the regenerative repeater, signal regeneration is performed, so that deterioration of the signal-to-noise ratio is prevented. Regenerative repeaters are more expensive than linear repeaters It is. For this reason, equipment costs can be reduced by reducing the number of regenerative repeaters in the network design.

HUB converts a signal received at a station having a traffic demand into a client signal. HUB also branches the path to an appropriate route. HUB may have a regenerator for each channel. The HUB performs signal reproduction and reproduction signal amplification by the reproducer as necessary. It is not necessary that each channel of HUB has a regenerator. Therefore, equipment costs can be reduced by reducing the number of regenerators provided for each channel.

Non-Patent Document 1 discloses a conventional design method of a communication network. In Non-Patent Document 1, HUBs are first installed in all the stations that have traffic demand. This HUB has regenerators for all channels and performs signal reproduction and reproduction signal amplification. Next, only the strength loss of the multiplexed signal is verified, and a linear repeater and a regenerative repeater are installed between the stations based on the verification result. In such a network in which the reachability of signals between all the stations is guaranteed, shortest distance path routing is performed. In Non-Patent Document 1, such a method is used to efficiently utilize network resources such as a band and the number of wavelengths.

FIGS. 18 and 19 are flowcharts of network design based on Patent Document 1. Next, a method for designing a communication network based on the contents of Patent Document 1 will be described. In this realization method, the optimal placement of the regenerative repeater is performed in consideration of signal noise between certain linear terminal stations.

The terms used in the following description are defined. The temporary linear repeater and the temporary regenerative repeater indicate a linear repeater and a regenerative repeater which are assumed to be temporarily arranged in each node to calculate the accumulated noise-to-signal ratio. The cumulative noise-to-signal ratio is the total amount of noise-to-signal ratio (including the normalized noise amount) in a certain 3R section (regenerative repeater section) or provisional 3R section (temporary regenerative repeater section). The temporary 3R section indicates a section between the temporary regenerative repeater and the terminal station or between the temporary regenerative repeater and the regenerative repeater.

First, the total noise-to-signal ratio in the communication network is calculated (PS 0 1). The total noise-to-signal ratio is the noise-to-noise ratio between adjacent terminals and nodes and between each node. It is the total amount of the signal ratio.

Next, the number of regenerative repeaters required for communication between the terminal stations is calculated (PS02). The number of regenerative repeaters required between terminal stations is calculated by Equation 1.

1]

(Number of regenerative repeaters required between terminal stations)

(Total noise to signal ratio)

, (Noise determination value that can be transmitted without a regenerator) Next, the noise amount determination value in each 3R section is calculated (PS03). Each provisional 3R section is calculated as follows: The noise-to-signal ratio is designed so as not to exceed the noise amount determination value calculated in PS 03. The noise amount determination value in each 3R section of the communication network is calculated by Expression 2.

[Equation 2]

(Each ³ noise in ^R interval transliteration value) end station ^ g numeric) "Next, in order from one end station P 1 to the other end station P 2, is temporary regeneration repeater to the position of each node arrangement Then, the cumulative noise-to-signal ratio of the provisional 3R section including this node is calculated (PS 04).

Next, it is determined whether or not the value of the cumulative noise-to-signal ratio calculated in P S04 exceeds the noise amount determination value calculated in P S03 (P S 05). If the value of the accumulated noise-to-signal ratio does not exceed the noise amount determination value (PS 05—YES), the temporary regenerative repeater immediately before the previous node, ie, the node where the temporary regenerative repeater is currently located (current node). It is determined whether the node in which is located is a temporary linear repeater, a transmitting terminal, or a regenerative repeater, and the allocation processing of the linear repeater is performed based on the determination result (PS06). . In the linear repeater assignment process, if the previous node is a temporary linear repeater, the previous node is determined to be a linear repeater. On the other hand, if the previous node is the transmitting terminal or regenerative repeater, nothing is executed and the process moves to the next process.

After the processing of PS 06, it is determined whether the current node is the receiving terminal station (PS 07). If the current node is the receiving terminal station (PS 07—YES), the system design processing ends (PS 08).

On the other hand, if the current node is not the receiving end station (PS 07—NO), the current node is replaced with a temporary linear repeater instead of a temporary repeater, and the node to be processed is moved to the next node (PS 09—NO). ), The processing for this node is executed. That is, in the case where the temporary regeneration relay device is provided in the next node, the processes after PS04 are executed.

In P S05, when the noise-to-signal ratio exceeds the noise amount determination value (P S05-1 NO), it is determined whether or not the previous node is a temporary linear repeater (P S 1

0). If the previous node is not a temporary linear repeater (PS 10—NO), it is determined that communication is not possible in the design target network (PS 11). On the other hand, if the previous node is a temporary linear repeater (PS 10 -YES), this previous node is determined as a regenerative repeater, not a temporary linear repeater. Then, the process after PS04 is executed without moving the node to be processed to the next node (PS12: regenerative repeater allocation process).

FIG. 20 is a diagram showing an example of device arrangement between terminal stations in a communication network designed based on Patent Document 1. In the communication network shown in FIG. 20, 11 nodes P2 to P12 are arranged between the terminal station P1 and the terminal station P2. The following describes how the linear repeater and the regenerative repeater are arranged based on Patent Document 1 in the communication network shown in FIG.

First, the total noise-to-signal ratio is calculated as 0.20 X 12 = 2.40 (P S 0

1) Next, the number of regenerative repeaters required between the terminal station P1 and the terminal station P13 is calculated as "2" by Equation 1 (PS02). Here, it is assumed that the noise amount determination value at which communication is possible without a regenerator is “1.00”. Next, the noise amount determination value in each 3R section is calculated to be “0.80” by Equation 2 (PS03).

Next, the processes from PS 04 onward are executed for the nodes P2 to P12. As a result, regenerative repeaters are arranged at nodes P5 and P9, and linear repeaters are arranged at the remaining nodes. Therefore, the cumulative noise-to-signal ratios in the 3R section are all 0.80, and are equalized. [Patent Document 1]

Japanese Patent Application No. 2 0 0 2-2 0 4 4 6 1

[Non-Patent Document 1]

P. Arijs, B. Van Caenegem, P. Demeester, P. Lagasse, W. Van Parys and P. Achten, "Design of ring and mesh based WDM transport networks," Optical Networks Magazine, Vol. 1, no. pp. 25-40, July 2000. Disclosure of the Invention

In the design method described in Non-Patent Document 1, a regenerative repeater is always arranged in each station. For this reason, while signal performance is highly reliable, a redundant and inefficient communication network was designed in terms of equipment costs. In order to obtain an economical communication network by reducing the number of regenerative repeaters and regenerators, a detailed design that takes into account not only the loss of multiplexed signal strength but also noise and dispersion is required. However, if the minimum cost of equipment arrangement is implemented in the entire network, the number of combinations of arrangement of each equipment in each station becomes enormous, and the number of steps required for the design becomes large, which is not practical.

On the other hand, according to the design method described in Patent Document 1, signal performance is strictly verified and designed. However, the design method described in Patent Document 1 guarantees signal performance only between linear terminal stations. In an actual communication network, paths having different start points and end points intersect in a complicated manner, and signal regeneration is performed for each channel. For this reason, even if linear repeaters, regenerative repeaters, and regenerators in HUBs are efficiently arranged in linear sections, if they are regarded as the entire communication network, redundant regenerative repeaters and HUBs Regenerator will be generated. In particular, there is a possibility that redundant regenerators will be placed in the HUB at the branch point in the mesh communication network. As described above, conventional communication network design methods do not realize efficient (eg, low equipment cost) design for communication networks that are not linear. In view of the above, an object of the present invention is to provide a network design apparatus capable of designing a communication network realized at an economical equipment cost in designing a non-linear communication network.

In order to solve the above problem, the present invention has the following configuration. First of the present invention An aspect is a network design device, which includes a dividing unit, an assigning unit, a path forming unit, and a deleting unit.

The network design device assigns devices, such as linear repeaters and regenerative repeaters, that compensate for signal degradation to a network having a plurality of channels and including branch nodes. The network design device allocates a device for terminating the channel to each channel in the branch node. The device for terminating the channel is a device that compensates for the deterioration of the signal of the channel and performs signal reproduction and reproduction signal amplification, such as a regenerator. A regenerator is a device that performs light-to-electricity conversion, and performs signal regeneration, reproduced signal amplification, and electric-to-light conversion. That is, a device for terminating a channel is a device capable of terminating a channel, converts a signal of the channel from light to electricity, performs signal reproduction and amplification of a reproduced signal, and then changes from electricity to light again. It is a device to change.

The dividing means assigns a device that terminates one or more channels to be used for the terminal node and each branch node (all channels if all channels are to be used). By this allocation, a plurality of linear partial networks having a preset terminal node or each branch node as a terminal node are virtually generated.

The allocating means allocates a device that compensates for signal deterioration, such as a linear repeater or a regenerative repeater, to the nodes constituting each partial network based on the signal performance. For example, the allocating means allocates a linear repeater and / or a regenerative repeater to each of the above nodes.

The path forming means forms a specific path by combining the partial networks to which the devices are allocated by the allocating means. For example, this particular path is a path that requires traffic in the network under design.

The deletion unit deletes the device terminating the channel allocated to the branch node based on the signal performance for each path formed by the path formation unit. The dividing means, the allocating means, the path forming means, and the deleting means may be means realized by executing a specific program by the information processing device, or may be realized as a hardware chip. May be. That is, the second of the present invention An aspect is a program for causing an information processing device to execute such processing.

According to the first aspect or the second aspect of the present invention, for a network having a branch node, that is, for a non-linear network, a redundant “terminal terminating device” assigned to a channel of the branch node is deleted.

For example, the deleting unit may determine whether the signal formed by the path forming unit from the terminal node or the node to which the regenerative repeater is assigned (the calculation start node) along the path along the path formed by the path forming unit. Calculate the cumulative value. Then, a branch is made to a section from the calculation start node to another terminal node or a node (maximum value node) to which a regenerative repeater is assigned, in which the accumulated value of signal performance degradation does not exceed a specified value and becomes a maximum value. If there is a node, delete the device that terminates the channel assigned to this branch node.

At this time, the deletion unit deletes the device that terminates the channel corresponding to the path formed by the path formation unit (that is, the path currently being processed) at the branch node. Note that the specified value is a value indicating that signal reproduction is possible if the accumulated value of signal performance degradation does not exceed this value in the network. For this reason, it is possible to reduce the equipment cost of the device that terminates the channel.

The first aspect according to the present invention further comprises a channel allocating means for routing a path based on a traffic demand between the nodes and allocating a channel to the routed path, wherein the dividing means comprises: May be configured to generate a partial network based on a path routed according to the above, and the path forming unit may form a path routed by the channel allocating unit as a specific path.

Further, the first aspect according to the present invention further comprises a continuation determining means for determining whether or not to continue the processing after the processing of the deleting means, wherein the channel allocating means is configured such that If it is determined to continue, a new path is routed, and the dividing unit, the allocating unit, the path forming unit, and the deleting unit perform processing on the path newly routed by the channel allocating unit. I'll do it It may be configured as follows.

Further, the channel allocating means according to the first aspect of the present invention is configured to search for an available path based on signal performance from a current communication network device installation state when routing a new path. May be.

Further, the dividing means according to the first aspect of the present invention may be configured so that a partial network having a branch node having two connection routes as a terminal node is not configured.

Further, the first aspect according to the present invention may be configured so as to further include an output unit that outputs, after the processing of the deletion unit, a device that has been assigned the harmful IJ to each node.

Further, the continuation determining means of the first aspect according to the present invention determines that the processing is to be continued when the equipment cost in the newly designed network is lower than the equipment cost in the previously designed network. It may be configured as follows.

Further, the continuation determination means of the first aspect according to the present invention may be configured to determine that the processing is continued when an unset path (new path) exists. A third aspect of the present invention is a branching device installed in a branch office of a branch node configuring a network, comprising: a network having a plurality of channels and including a branch node; A step of allocating a device that terminates one or more channels to be used to divide the network into a plurality of linear sub-networks each having a pre-set terminal node or each branch node as a terminal node; and Assigning a linear repeater and / or a regenerative repeater to the nodes constituting the network based on the signal performance; forming a specific path by combining the sub-networks to which the devices are assigned; and For the path, terminate the channel assigned to the branch node based on the signal performance. It is designed by the steps of: a deletion of an apparatus run.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to design a communication network which is efficient (for example, the equipment cost is low) and is realized at an economical equipment cost for a non-linear communication network.

The present invention also provides a network design device having the above-described features. It can also be specified as a network system to be designed. BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows an example of a network model.

FIG. 2 is a diagram illustrating a configuration example of HUB.

FIG. 3 is a diagram showing hardware blocks of the network design device. FIG. 4 is a diagram showing function blocks of the network design device.

FIG. 5 is a diagram showing an example of topology information.

FIG. 6 is a diagram showing an example of topology information.

Figure 7 shows an example of traffic demand information.

FIG. 8 is a diagram illustrating an example of signal performance information.

FIG. 9 is a diagram showing an example of path route information.

FIG. 10 is a flowchart of the first operation example,

FIG. 11 is a diagram showing a specific example of the noise-to-signal ratio.

Figure 12 is a diagram showing an example of network design.

FIG. 13 is a flowchart of the second operation example.

'' Fig. 14 is a flowchart of the second operation example.

Figure 15 shows an example of a network model.

FIG. 16 is a diagram showing a specific example of the noise-to-signal ratio.

Figure 17 shows an example of network design.

FIG. 18 is a flowchart of the related art.

FIG. 19 is a flowchart of the related art.

FIG. 20 shows an example of a network model designed by the conventional technique. BEST MODE FOR CARRYING OUT THE INVENTION

Next, the network design apparatus according to the embodiment of the present invention will be described with reference to the drawings. The description of the present embodiment is an exemplification, and the configuration of the present invention is not limited to the following description.

The network design device according to the present invention assumes a virtual network model Then, the network is virtually designed on the device. The designed network configuration is output by the network design device as a display, printer, or data file. The network design apparatus according to the present invention is, for example, a CAD (Computer Aided Design) system for network equipment.

[Network]

FIG. 1 is a diagram showing a model of a network to be designed by a network design apparatus according to the present invention. The network in FIG. 1 includes terminal nodes 1 to 3, branch nodes 4, and nodes 5 to 10. Each node indicates a station. For this reason, each node is assigned a device to be installed in the station building. In other words, the devices assigned to the nodes in the network design are actually installed in the station building.

Each node is connected by a link. A link indicates a fiber. That is, in practice, a fiber is installed as a link, and each station or a device in the station is communicably connected by a fiber.

The end nodes 1 to 3 are connected via the branch node 4 respectively. Nodes 5 to 10 are arranged between the end nodes 1, 2, and 3 and the branch node 4, respectively. In the network shown in Fig. 1, network design is performed on the assumption that there is a traffic demand between end nodes 1 and 2 and between end nodes 1 and 3 for each channel. .

Each terminal node 1 to 3 is assigned a terminal device. HUB is allocated to the branch node 4. Also, a linear repeater or a regenerative repeater is assigned to each of the nodes 5 to 10 as a result of the network design.

FIG. 2 is a diagram illustrating a configuration example of the HUB assigned to the branching node 4. HUB is provided with a regenerator 11 and a channel 12.

The multiplexed signal is input to HUB. When the multiplexed signal is input to the HUB, it is divided into signals for each channel 12. The signal of each channel 12 is transmitted in the hub according to a predetermined path, and is output to the outside by being multiplexed again. A regenerator 11 is assigned to a specific channel 12 in the HUB after network design. The regenerator 11 is a device that performs light-to-electricity conversion, and performs signal reproduction, reproduced signal amplification, and electric-to-light conversion.

〔System configuration〕

FIG. 3 is a diagram showing a hardware block of the network design device 13 according to the present invention. The network design device 13 is configured using an information processing device such as a personal computer workstation. In terms of hardware, the network design device 13 includes a display unit 14, an input unit 15, an arithmetic processing unit 16 (CPU), and a storage unit 17 (main storage (RAM), auxiliary storage) connected via a bus. Equipment (flash memory, hard disk, etc.).

The display unit 14 operates as a user interface. The display unit 14 is configured using an output device such as a liquid crystal display, a CRT (Cathode Ray Tube), or a printer. The display unit 14 outputs the result of the processing by the arithmetic processing unit 16 and the like.

The input unit 15 transfers various instructions, data, and the like to the arithmetic processing unit 16 when operated by the user. Examples of data input from the input unit 15 include topography information, traffic demand information, and signal performance information. The input unit 15 includes, for example, an input device (eg, a keyboard and a pointing device) as a user interface, a network interface (eg, a LAN interface, a WAN interface), and various drives (eg, a floppy disk drive, a CD-ROM drive, It is configured using a DVD-ROM drive, MO drive, flash memory reader) and the like.

FIG. 4 is a diagram showing a function block in the arithmetic processing unit 16 of the network design device 13. The arithmetic processing section 16 operates as a section dividing section 18, a section designing section 19, and a regenerator arrangement changing section 20 by executing the program according to the present invention stored in the storage section 17.

The section dividing unit 18 performs a section dividing process. Executing section division processing A network to be designed is divided into one or more linear partial networks 21 (21a to 21c in FIG. 1). For example, the network shown in FIG. 1 is divided into three partial networks 21 a to 21 c that respectively connect the end nodes 1 to 3 and the branch node 4. HUB is allocated to branch node 4 by executing the section division processing. A regenerator 11 is assigned to one or more channels that are scheduled to use the HUB (in this example, all channels that have the HUB are scheduled to be used). As described above, by executing the section dividing process, the network having the branch node 4 is divided into one or more linear partial networks at the branch node 4.

The section design unit 19 executes a section design process. By executing the section design processing, a linear repeater or a regenerative repeater is efficiently allocated to each of the nodes 5 to 10 constituting each subnetwork 21. For efficient allocation of linear repeaters and regenerative repeaters, the method described in Patent Document 1 is basically applied. In addition, by executing the section design processing, each partial network 21 is synthesized into one or more paths. This path is a path that is attracting attention in network design, that is, in FIG. 1, two paths, a path connecting terminal nodes 1 and 2, and a path connecting terminal nodes 1 and 3 It is.

The regenerator arrangement change unit 20 executes a regenerator arrangement change process. By executing the regenerator placement change processing, the signal performance of each path of interest is verified. Then, in HUB assigned to the branch node 4, the redundant regenerator 11 is deleted. As a result, for example, as shown in FIG. 2, the inside of the HUB has a structure in which a regenerator 11 is assigned to a partial channel 12.

The storage unit 17 stores various programs (OS, applications, etc.). The storage unit 17 stores topology information, traffic demand information, signal performance information, and path route information as information used for network design.

5 and 6 show examples of topology information. The topology information is composed of fiber link information shown in FIG. 5 and node position information shown in FIG. First, the fiber link information will be described with reference to FIG. Fiber link The information table has, as fields, link ID, node ID 1, node ID 2, length, and fiber type.

The link ID indicates a link identifier unique to the entire communication network. Node ID 1 indicates an upstream connection node of the fiber link. Node ID 2 indicates a downstream connection node of the fiber link. Length indicates the physical length of the fiber. The length is expressed in km (km) in the table shown in Fig.5. The fiber type indicates the type of fiber used. The fiber type is used when characteristics such as signal deterioration are determined.

A link indicated by a certain link ID is a link whose upstream and downstream sides are respectively terminated by nodes indicated by the nodes ID1 and ID2. This link is made up of fibers of the type indicated by the fiber type and of the length indicated in the table.

Next, the node position information will be described with reference to FIG. The table of the node position information has node ID, latitude, and longitude as fields.

Node ID indicates a node identifier that is unique throughout the communication network. This node ID corresponds to node ID 1 and node ID 2 in the fiber link information. Latitude and longitude indicate the geographic coordinates of the node. The latitude and longitude may be specified by any description method. For example, north latitude and east longitude may be expressed using positive values, and south latitude and west longitude may be expressed using negative values. In addition, the geographic coordinates of the node may be specified by values other than latitude and longitude.

The straight-line distance between nodes can be calculated from the latitude and longitude of each node. However, in practice, nodes are not always connected by linear links. For this reason, the fiber link information of the topology information needs to have the length of each link as a field.

FIG. 7 is a diagram illustrating an example of traffic demand information. Hereinafter, the traffic demand information will be described with reference to FIG. The traffic demand information table has, as fields, demand ID, start point, end point, bandwidth, and number of channels.

Demand ID is a unique identifier corresponding to each traffic demand. The starting point indicates the node ID of the source node of the traffic. The end point is the traffic reception Indicates the node ID of the node. The number of channels indicates the number of paths actually set.

FIG. 8 is a diagram illustrating an example of signal performance information. Hereinafter, the signal performance information will be described with reference to FIG. The signal performance information table has fields such as fiber type, multiplex number, fiber loss, and noise-to-signal ratio. The signal performance information table is used to obtain the noise-to-signal ratio from the fiber type, multiplex number, and fiber loss value.

The fiber type corresponds to the fiber type in the fiber link information table. FIG. 8 shows SMF (Single-Mode optical fiber) and NZ—DSF (Non-Zero Dispersion Shifted single-mode optical fiber) as examples. The number of multiplexing, fiber loss, and noise-to-signal ratio indicate the characteristics of each fiber type: Fiber loss is in dB, noise-to-signal ratio is in dB / km, which occurs in linear repeaters. The noise-to-signal ratio of the noise depends on the characteristics of each fiber type indicated in the signal performance information, and the following describes how to determine the noise-to-signal ratio: For example, the fiber type is NZ — DSF and the multiplex number is 1. 76 Let us describe the case where the fiber loss is 15 dB.

First, the values of 23 dB and 5 are given from the characteristics of the fiber type as the dB value that must not be exceeded and the number of links that must not be exceeded in one fiber. Also, assume that the determination value of the noise-to-signal ratio based on the entire section is 1.00.

In this case, the amount of noise (reference maximum loss) that can be communicated without a regenerative repeater is obtained as 115 dB by multiplying the two values given by the characteristics of the above fiber types. Then, the noise-to-signal ratio of each link is obtained as 0.130 by dividing the fiber loss by the reference maximum loss.

FIG. 9 is a diagram illustrating an example of the path route information. Hereinafter, the path route information will be described with reference to FIG. The path route information table has, as fields, a path ID, a path route, and a node with a regenerator.

The path ID indicates a unique identifier for the entire communication network of the path corresponding to one channel of the traffic demand. The path route information indicates the nodes through which the path passes in order. A node with a regenerator is one of the nodes 5 to 10 through which the path passes. Indicates which node is being used. That is, the node with the regenerator indicates the node ID of the node to which the regenerative repeater is assigned.

[First operation example]

Next, a first operation example of the network design device 13 according to the present invention will be described. FIG. 10 is a flowchart of the first operation example. In the following description, it is assumed that the network model to be designed is the network shown in FIG.

In the first operation example, first, topology information, traffic demand information, and signal performance information are input to the network design device 13 (S01). As the topology information, for example, information corresponding to a network model as shown in FIG. 1 is input. As traffic demand information, information indicating that there is traffic demand of one optical path from terminal node 1 to terminal node 2 and one channel of optical path from terminal node 1 to terminal node 3 is input. .

Next, the shortest path is routed, and the appropriate wavelength is assigned to the traversing link (S02). That is, optical paths are routed between the terminal nodes 1 and 2, and between the terminal nodes 1 and 3, and wavelengths are assigned to the respective optical paths so that wavelengths do not collide.

Next, a device that terminates one or more channels to be used (all channels in this example) is assigned to a node having a linearity of 1 or more (S03). A device that terminates a channel is a device that includes at least a regenerator. That is, by the processing of SO 3, an operation similar to that in which a regenerator is assigned to at least all the channels occurs in such a node. The linearity indicates the number of links connected to a certain node. For example, terminal nodes 1 to 3 have a linearity of 1. Branch node 4 has a linearity of 3. And nodes 5 to 10 have a linearity of 2.

Next, the network subject to network design is divided into one or more linear sub-networks separated by nodes with a linearity of 1 or more (SO 4). Specifically, the network shown in FIG. 1 is divided into linear partial networks 21a, 21b, and 21c. The above processing is executed by the section dividing unit 18 as section dividing processing. Next, the section designing process is performed by the section designing section 19. Specifically, based on the method described in Patent Document 1, allocation of a linear repeater and a regenerative repeater to each of the partial networks 21a to 21c is performed (S05). The processing of S05 will be described more specifically below.

First, the noise-to-signal ratio at each link (that is, the noise-to-signal ratio of the fiber between adjacent nodes 1 to 10) is determined based on the input information. FIG. 11 is a table showing the noise to signal ratio obtained for each link. Based on this table, the noise-to-signal ratio determination value in each 3R section is calculated to be 0.80 using Expressions 1 and 2.

Next, the network design starts from the terminal node 1. At node 5, the cumulative noise to signal ratio is 0.40, and at node 6, the cumulative noise to signal ratio is 0.80. Therefore, a linear repeater is assigned to node 5, and a regenerative repeater is assigned to node 6. Such network design processing is continued according to the flowcharts of FIGS. 18 and 19, and linear repeaters are assigned to nodes 5, 8, and 10, and regenerative repeaters are assigned to nodes 6, 7, and 9, respectively.

Next, the regenerator arrangement changing section 20 executes a regenerator arrangement changing process. Specifically, the processing of S06 and S07 is performed.

First, the cumulative value of the noise-to-signal ratio is calculated for each node in each path. In this case, the cumulative value of the noise-to-signal ratio is calculated without considering the regenerator 11 assigned to the channel in the HUB of the branch node 4. Then, at the branch node that has passed without exceeding the specified value (the noise amount determination value in each 3R section), the regenerator 11 assigned to the channel corresponding to the considered path is deleted. (S06). Hereinafter, the processing of SO 6 will be described with a specific example of a path connecting the terminal node 1 and the terminal node 2. At the branch node 4, the accumulated value of the noise-to-signal ratio is 0.40, which does not exceed the specified value. That is, the branch node 4 is passed without the accumulated value of the noise-to-signal ratio exceeding the specified value. Therefore, in the branch node 4, the regenerator 11 assigned to the channel corresponding to the path connecting the terminal nodes 1 and 2 is deleted.

Next, it is determined whether or not the processing of S06 has been executed for all paths (S 0 7). Therefore, the processing in S06 is also performed on the remaining paths, that is, the paths connecting the end node 1 and the end node 3 (SO7-NO). By this processing, the regenerator 11 assigned to the channel corresponding to the path connecting the end node 1 and the end node 3 at the branch node 4 is also deleted.

If it is determined that the processing for all the paths has been performed in the processing of S07 (SO7-YES), the devices (linear repeater, reproduction relay device, reproduction in HUB) assigned to each node are A parts list of the container 11 1) is created and output (SO8).

[Operation and effect of the first operation example]

FIG. 12 is a diagram showing the configuration of a network based on the output component list, that is, the configuration of the network designed by the processes S01 to S07 by the network design device 13. In the first operation example, the network is divided into one or more linear partial networks by the section dividing process by the section dividing unit 18. By the section designing process by the section designing unit 19, the linear repeater and the regenerative repeater are assigned to the nodes of each partial network. Then, by the regenerator arrangement changing process by the regenerator arrangement changing unit 20, a part of the regenerator 11 allocated to all the channels in the HUB at the branch node 4 is reduced. Therefore, an efficient communication network can be designed even in a network including the branch node 4, that is, a non-linear network. Specifically, first, even in a non-linear network, an efficient arrangement of the linear repeater and the regenerative repeater, that is, an efficient network design becomes possible. Also, among the regenerators 11 assigned to the channels in the HUB at the branch node 4, the redundant regenerator 11 is deleted. Therefore, it is possible to reduce the cost (equipment installation cost) in designing a non-linear network.

[Second operation example]

FIGS. 13 and 14 are flowcharts of the second operation example. FIG. 15 is a diagram illustrating a model of a network to be designed in the network according to the second operation example. Next, a second operation example of the network design device 13 according to the present invention will be described. The processing of S10 to S15 in the second operation example is the same as that of S02 to S15 in the first operation example. This processing is similar to the processing of S07. Hereinafter, points of the second operation example different from the first operation example will be described.

In the second operation example, a variable called equipment cost (equipment cost) is used. In the second operation example, first, topology information, traffic demand information, and signal performance information are input to the network design device 13. Also, the value of the equipment cost is set to infinity (S09). As the topology information, for example, information corresponding to a network model as shown in FIG. 15 is input. As traffic demand information, information indicating that there is a traffic demand of one optical path from terminal node 1 to terminal node 2 and one channel of optical path from terminal node 1 to terminal node 3 is input. Next, the shortest path is routed and the appropriate wavelength is assigned to the traversing link (S10). Here, as a path from terminal node 1 to terminal node 3, a path passing through nodes 22 to 24 is set. The path from the terminal node 1 to the terminal node 2 is set as a path passing through the nodes 5 to 8 and the branch node 4 as in the first operation example.

Next, a device that terminates one or more channels to be used (all channels in this example) is assigned to a node having a linearity of 1 or 3 or more (S11).

Next, the network to be designed is divided into one or more linear partial networks separated by nodes having a linearity of 1 or more (S12). By this processing, the partial networks 21a, 21b, 21d are set. This partial network 21d includes nodes 22 to 24. In this description, it is assumed that the fiber used for this partial network 21d is a poor quality fiber, that is, a fiber having a high noise-to-signal ratio value.

Next, the section designing process is executed by the section designing section 19 (S13). At this time, first, the noise-to-signal ratio at each link (that is, the noise-to-signal ratio of the fiber between adjacent nodes 1 to 8 and 22 to 24) is determined based on the input information. Figure 16 is a table showing the noise-to-signal ratio obtained for each link. Based on this table, using Equations 1 and 2, the noise-to-signal ratio determination value in each 3R section is calculated as 0.80. After that, a linear repeater and a regenerative repeater are assigned to each node as in the process of S05. In this case, the partial network 2 1 c is Since it is not included in the path set in S10, it is not subject to processing.

Next, a regenerator arrangement changing process is executed by the regenerator arrangement changing section 20 (S14, S15). At the point in time when the first round of processing at S15 has been completed (at the point at which it has been determined that processing has been completed for all paths in the first round of S15), linear repeaters are assigned to nodes 5 and 8, Nodes 6, 7, 22, 23, and 24 are assigned regenerative repeaters.

Next, it is determined whether the equipment cost has decreased (S16). Specifically, the equipment cost of the network designed at the time of the determination in S16 is calculated, and the calculated value is compared with the value of the equipment cost held as a variable. The equipment cost is calculated, for example, by adding up the numerical values of the costs set for each device. If the newly calculated value is small, that is, if the equipment cost is reduced (S16—YES), a new path is set (S17), and the network design for this new path is executed. (S11 to S15). For example, in the first decision in S16, the value of the equipment cost held as a variable is infinite, so the processing after S17 (the processing after the second round) is always performed.

In the second operation example for the network shown in Fig. 15, in the rerouting process of S17, nodes 5, 6, 9, 10 and branch node 4 are connected as paths from terminal node 1 to terminal node 3. The path to be passed is set. After that, the regenerative repeaters and linear repeaters are assigned to the nodes 9 and 10 by the processing of S12 to S15, and the regenerative repeaters assigned to the nodes 22 to 24 are deleted. In addition, the channel regenerator i i corresponding to the path from terminal node 1 to terminal node 3 in the HUB is also deleted.

After this processing, the processing of S16 is executed again. In this case, two regenerative repeaters are reduced and one linear repeater is added. Here, it is assumed that the cost of the regenerative repeater is higher than that of the linear repeater, and that the equipment cost is reduced. Therefore, the processes of S17 and S11 to S16 are executed again. At this time, there is no other path, so the equipment cost does not decrease (S16—NO). Therefore, a component list of the devices (linear repeaters, regenerative repeaters, and regenerators 11 in the HUB) assigned to each node is created and output (S18). FIG. 17 is a diagram illustrating an example of a network design according to the second operation example. The regenerative repeaters at nodes 22 to 24 assigned in the first round design are deleted in the second round design. As a result, the device allocation is the same as that of the network designed by the first operation example (see Fig. 12).

In the process of S16 in the second operation example, it is determined whether or not the processes of S11 to S15 have been performed for all the paths, not whether the facility cost has decreased. May be. In this case, if there is a path for which the processing of S11 to S15 has not yet been performed, the processing of S11 to S15 is performed for the new path through the processing of S17. Will be implemented. When the processing of S11 to S15 has been performed for all the paths, the processing of S18 is performed. In this case, in the processing of S18, an output based on the design of the network with the lowest equipment cost is performed.

In the process of S17 in the second operation example, routing may be executed so as to preferentially set a shorter distance path. In this case, in addition to the reduction of the equipment cost, there is an effect that a shorter path is set.

[Operation and effect of the second operation example]

According to the second operation example, when a plurality of paths can be set as a path from a certain source node to a receiving node, efficient allocation of a linear repeater and a regenerative repeater is performed for each path. The regenerator 11 is deleted. Then, it is determined whether or not the cost is lower than the equipment cost in the previous network design, and the output is performed when the cost is no longer lower. Therefore, even in a network in which a plurality of paths can be set, it is possible to design a network with lower equipment cost. Industrial applicability

INDUSTRIAL APPLICATION This invention is applicable to the industry which provides the service regarding the design of the network which reduced the equipment cost.

Claims

The scope of the claims

1. A network having a plurality of channels and branching nodes and a plurality of paths can be set in advance by allocating a terminating node and a device for terminating one or more channels to be used to each branching node. Dividing means into a plurality of linear sub-networks each having a terminating node or each branching node as a terminating node;

Allocating means for allocating a linear repeater and / or a regenerative repeater to the nodes constituting each partial network based on the signal performance of the fiber allocated between the nodes;

Path forming means for forming a specific path by combining the respective partial networks to which the devices are allocated by the allocating means;

A network design apparatus comprising: a deletion unit that deletes a device that terminates a channel allocated to a branch node based on signal performance for each path formed by the path formation unit.

2. Channel allocation means for routing a path based on the traffic demand between each node and allocating a channel to the routed path, wherein the division means is configured based on the path routed by the channel allocation means. Generate a partial network,

The path forming means forms a path routed by the channel allocating means as a specific path

The network design apparatus according to claim 1.

3. After the processing of the deleting means, further comprising a continuation determining means for determining whether or not to continue the processing,

The channel allocating means routes a new path when the continuation determining means determines to continue the processing,

3. The network design apparatus according to claim 2, wherein said dividing means, said allocating means, said path forming means, and said deleting means execute processing on a path newly routed by said channel allocating means.

4. The channel allocating means, when routing a new path, uses the current communication 4. The network design apparatus according to claim 3, wherein a request is made to search for an available path based on the signal performance from the network device laying state.

5. The network configuration according to any one of claims 1 to 4, wherein the division unit does not form a partial network having a branch node having two connection routes as a terminal node.

6. The deletion unit may determine that the cumulative value of signal performance degradation from the terminal node or the node to which the regenerative repeater is assigned does not exceed a specified value for the path formed by the path formation unit. If there is a branch node in the section up to the other terminal node or the node to which the regenerative repeater device is assigned the maximum value, the device that terminates the channel assigned to this branch node is deleted. 6. The network design apparatus according to any one of 1 to 5.

7. The network device according to any one of claims 1 to 6, further comprising output means for performing an output indicating a device assigned to each node after the processing of the deletion means.

8. The network design according to claim 3, wherein the continuation determining means determines that the processing is continued when the equipment cost in the newly designed network is lower than the equipment cost in the previously designed network. apparatus.

9. The network design apparatus according to claim 3, wherein the continuation determining means determines that the process is continued when an unset path (new path) exists.

10. A network that has multiple channels and includes branching nodes is assigned to a terminal node and a device that terminates one or more channels to be used for each branching node. A step of dividing the node or each branch node into a plurality of linear partial networks having terminal nodes;

Assigning a linear repeater and / or a regenerative repeater to nodes constituting each partial network based on signal performance;

Forming a particular path by combining each of the sub-networks to which the device is assigned;

Performing, for each of the formed paths, removing a device terminating the channel allocated to the branch node based on the signal performance; and For causing an information processing apparatus to execute the program.

1 1. A branching device installed in the branch office of a branch node that forms a network. A network including a plurality of channels and including a branching node is scheduled to be used for a terminal node and each branching node. Allocating a device that terminates one or more channels to divide the network into a plurality of linear sub-networks each having a preset terminal node or each branch node as a terminal node;

Performing, for each path formed, removing a device terminating the channel allocated to the branch node based on the signal performance; and

A branching device designed according to the above, wherein the device terminating the channel has been deleted.

1 2. Preliminary setting of a network having a plurality of channels, branching nodes, and a plurality of paths by assigning a terminal node and a device that terminates one or more channels to be used to each branch node. Dividing means into a plurality of linear sub-networks each of which has a terminal node or each branching node as a terminal node.

Allocating means for allocating a linear repeater and / or a regenerative repeater to each of the partial nets and the nodes constituting the network based on the signal performance of the fiber allocated between the nodes;

A network system designed by a network design apparatus, comprising: a deleting unit that deletes a device terminating a channel allocated to a branch node based on signal performance for each path formed by the path forming unit.